Assymetrical electrical conductor.



m 673,953. Pat md m l4, ISOI.

L.' w. HILDBURGH.

ASYHI ETRICAL ELECTRICAL CONDUCTOR.

(Application filed Apr. 94, 1899.)

(No Model.)

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direction.

UNITED STATES PATENT OFFICE.

LE0 ALTER HILDBURGH, on NEW YORK, NQY.

ASYMMETRIGAL ELE CTRICAL CONDUCTOR.

SPECIFICATION forming part Of Letters Patent No. 673,953, dated May 14, 1901.

Application filed April 24, 1899. Serial No. 714,187, (No model.)

tors, of which the following is a specification.

This invention relates tothe class of electricalconduciors known as asymmetrical conductors and which oppose thepassage of a current in one directionwhile freely per-,

mitting the flow. of a current in the opposite In my application, Serial No. 659,376, filed November 22, 1897, I described such a conductor. One form of conductor therein described consists of inert and oxidizable electrodes dipping,.respectively, into neutral and oxidizing electrolytes and producing a negligible current. By a neutral electrolyte,as explained in that application, ismeant an electrolyte which has no action on either the electrode immersed. in it or on the other liquid in the cell, The neutral electrolyte when. the oxidizing-electrolyte is removed is neutral only toward the inert electrode and may combine with the material of.

the other electrode. I have found that the oxidizing-electrolyte canin some cases be dispensed with, the conductor then consisting of. an inert and an oxidizable electrode in an I electrolyte neutral to the inertelectrode. The

oxidizable or soluble electrode in a cell of this kind is continually dissolved by the action of the current passing during the operation of the device. If the electrolyte surrounding the active electrode be a solution of a salt of a metal other than that of the active electrode,

the passage of the current will cause the production of an electrolytev difiering from the original electrolyte and the cell will fall into the category of two-liquid cells. To remove the electrolyte thus formed, recourse may be had to theagitationof the electrolyte, to the use of an activeelectrode of a substance Whose salt (or other compound formed) diifuses rapidly in the main mass of liquid or is not readny electrolytically decomposable, or to the use of an active electrode of a material a solution of whose salt forms the electrolyte. The action supposed to take place in singleliquidcells is the following: When the current passes through the electrolyte from the active or soluble electrode toward the inert electrode, oxygen is deposited on the active and hydrogen on the passive electrode. The oxygen is immediately taken up by combination with the active electrode and is thus incapable of producing a counter electromotive force, while the electromotive force of the hydrogen deposited on the inert electrode is nontralized in whole or in part bythe electromo= tive force of the substance composing the ac tiveelectrode. The current passes then in this direction against little or nocounter elec-' tromot-ive force and flows freely. When, however, the current passes through the electrolyte from the inert to the activeelectrode, hydrogen is deposited on the active and oxygen on the passive electrode. This causes the production of a considerable counter electromotive force, against-which the current must flow, weakening it. If after the electrodes are covered with gas the impressed electromotive forceis nohigher than the counter electromotive foroe, no current canflow, making it possible by the use of a low enough ini-' pressed electromotive force to completely stop a current in one direction, while permitting the current in the opposite direction to pass.

The counter electromotive force is not produced instantaneously, but requires a certain time to rise to its full value, and this period is dependent on the area of the inert plate and the current flowing and in some cases is dependent upon the area of the active plate. Therefore in order to have the counter electromotive force rise quickly to its full value the size of the inert plate should be proportioned to the current flowing through it, and the larger the currentfiowing in the circuit the greater being the permissible size of the inert plate to maintain the same asymmetrical efficiency. Since the currentin the circuit is dependenton the constants of the circuit that is, its resistance, its capacity, its inductance, and the frequency of the impressed electromotive force-'the size of the inert plate should be proportioned to these constants. It is found that the size'of that plate bears a direct relation to the amount of asymmetry which may be produced in an alternating on rrent-that is, to the asymmetrical efliiciency of the device. To permit of the use I v The use of the gaseous elementshydrogen,

- of an alternating current'of an'electromotive force greater than can beeconomically asymmetrically aflt'ected by a single cell, a number tor. I have discovered that when this is done,

the plates remaining the same size as before, no matter what the impressed electromotive force may be, the asymmetrical efficiency is increased. Increasing the number of cells constituting the asymmetrical conductor increases the resistance; but this increase in resistance may be counterbalanced by enlarging the plates. By enlarging the platesin proportion as the number of cells in series increases the asymmetrical efficiency-and the resistance of the set of cells may be maintained nearly constant, whilethe ability to asymmetrically affect an alternating current of higher electromotive force. is obtained.

' The main requirement of the material forming'the active electrode is that it be able to combine with or otherwise neutralize the substance broughtto'it by the current in one direction, and of. the material composing the inert electrode that it be'incapable of combining with or, 'neutralizingfthat same substance when thecurr'ent passes'in the opposite'dire'ction, and of the whole combination 'ofjelectrodes and ele'ctrolytesthat it :be in-' capable of producing-by itself acurrent more thanjnegligible in 'comparison withthe final jfcurrent produced by-th'e rectificationiof the alternating current Many substances: can

be used for the factivefelectrode%'among'the metals copper, tin, silver, and hydrogen, and

' even, under the properconditions,zinc, iron, lead-mercury, and aluminium, and among the if nen-metals carbon,oxygen, chlorin, coal-gas, J &c.- Aluminlum'when-used under these'con-,

' 3 ditio'ns rectifies the alternatingcurrent in exactly the opposite sense from the rectifica- 'tion-pr'oducedwhen the aluminium becomes coated with a layer of high-resistance aluminium hydroxidor oxygen.

.Th'e rectification produced when the aluminium acts as a soluble electrode-permits the current to pass more freely through the electrolyte toward the inert plate; but the rectification produced. when the aluminium acts by virtue of .its film-forming properties permits the current to pass more freely through the electrolyte toward the aluminiu m be constructed by placing a carbon and a plate. The-former action generally takes place for only a limited time before the formation of the film which causes the latter action.

A very simple form of single-liquid cell can platinum plate inv dilute sulfuric acid, the active electrode being either'of gas-carbon or of charcoal. In the latter case the action is greatly improved by first heating the charcoal to a high temperature and plunging into water, dilute sulfuric acld,&c., thus increasing its efiective surface.

' 'oxygen, and cl11orinallows the device to be- .acid solutions andas the come continuous acting. When the solid ele ments' are used, they are gradually carried into solution and may in some cases stop the action of the device by forming a layer onby the platinum-black and .the'whole acting" I like an electrode composed exclusivelyof the gas. The elementary gases which-can thus be used with platinized platinum-arehydro gen, oxygen, and chlorin, the first'g ivi'ng the. 5

best results. hon, palladium-black,&c.can also be used in this same manner.

illustrates j a typical: continuous-acting cell constituting my improved asymmetrical con-.

Other materials s'uch as car-ff;

ductor; and Fig.2;illustrates' a number ,of

such cells connected in series with each other, the series ofcellslieing connected in series with a source of direct electroinotive force.

A small platinum ele,ctro'de'A,lcarried by a glass tube-B, and-'a large platinized'electrode '0 are placed in. a jsea led jar *D,-:c0ntaining dilute sulfuric acidEland" an atmosphere of hydrogen'gF. Theelectrodesaresupported by two terminals or bindingipostsG, mounted 1 upon and sealedinthe sealedcoverH. (The action of an alternating currentof not too]- high electromptive force partially rectified a by this; device' j causes hydrogen continually to pass from (Jgtfo A from A infbubbles to F, j a I and from]? through 0 to -A,'the' operation re-.

peating itself indefinitely. Platinum .need

not be used as the basis of the platinizing, any

inert conductorserviug equally well. I have I obtained good results from glass thinly plated with gold and platinized. Oxygen can be used in the same way in aoid'or alkaline solutions and chlorin in a solution 'ofh ydroe chloric acid, though neither gives such satisfactory results as'hydrogen. be used as an electrode in the ordinary form of continuous or non-continuous cell in com- 7 binationas,- for instance,.with lead or cop,- I

As peroxid' of lead it may be used in black oxid of copper.

per. in alkaline solutions.

It has been found that in certain cases in which gaseous electrodes are used the asym-i' metrical efiiciency-,.of the device may-beincreased byreducingthe pressure of the gas I which supplies the acti ye electrode. The reason for thisis suppo'sedto be that less work iswasted in the formation of bubbles at the" inert electrode than when the pressure is higher,' whi1e theefiectivenessof the active electrode is'but slightly reduced. It has also. ,7

Oxygen can also I In the accompanying drawings,Fig ure 1 being considered as insoluble.

been found that the addition of a comparatively small external electromotive force increases the asymmetrical efficiency, probably by supplying the excess of energy. necessary for the formation of the bubbles at the inert electrode. This is accomplished by placing a source of direct current I of small electromotive force in series with the set of similarly-formed cells A A (shown in Fig. 2,) comprising the asymmetrical conductor.

By a soluble electrode I mean an electrode whose active element is caused by the action of the current to dissolve, and not necessarily one in which the whole material is soluble. A copper electrode, for exam pie, is composed of a-material the whole of which is soluble under the conditions aifecting its use; but gaseous electrodes are considered soluble only sofar as concerns their gaseous elements. In a hydrogen electrode only the hydrogen is soluble, the material by which it is occluded In an oxygen electrode only the oxygen is soluble, the lead orcopper with which it is combined being considered insoluble. V

What I claim is- I 1. The combination of a soluble electrode and an inert electrode with an electrolyte, capable of producing no more than a negligible current, for the purpose of permitting the flow of current more freely from the soluble electrode through the electrolyte to the inert electrode than in the opposite direction.

2. In an asymmetrical conductor, the combination of a soluble electrode and an inert electrode with an electrolyte, means being provided for causing the substances carried from the soluble electrode to the inert electrode by electrolytic action to return to the active electrode.

3. In an asymmetrical conductor, the combination of a gaseous electrode andan inert electrode with an electrolyte for the purpose of permitting .the return of the gases discharged from the inert electrode to the active electrode from which they came.

4. In an asymmetrical conductor having soluble electrodes, the combination of gaseous electrodes and inert electrodes with an electrolyte under a pressure less than that of the atmosphere, forthe purpose of increasing the asymmetrical efficiency of the combination.

v5. An irreversible combination consisting of an inert and a soluble electrode with an electrolyte producing onlya negligible current, said combination permitting the flow of current more freely from the soluble electrode through the electrolyte to the inert electrode than in the opposite direction.

6. In an asymmetrical conductor, the combination with an electrolyte, of one or more is adapted to the nature of the work to be done.

7. In an asymmetrical conductor having soluble electrodes, the combination of several similar asym metrically-conducting parts in series in which the area of the inert electrodes is proportioned to the number of such parts, said inert electrodes being of such size as to maintain the electrolytic capacity of the conductor approximately the same while per- I [hitting the economical use of a proportionally higher impressed alternating electromotive force.

8. In an asymmetrical conductor, the combination of a series of asymmetrical cells and an external source of electromotive force,

such electromotive force being small as compared with the impressed alternating electromotive force, for the purpose of increasing the asymmetrical efficiency.

9. A device consisting of asolnble electrode and an inert electrode in an electrolyte capa: ble of producing no more than a negligible current and having a counter electromotive force greater when the current passes through 11. A device consistingiof .an electrolyte,

an electrode possessing the ability to cause oxygen to disappear from its surface, and an electrode notpossessing that ability, said device producing no more than a negligible current and permitting a greater flow of current in one direction than in the opposite direction.

12. A device consisting of a soluble electrode and an inert electrode in an electrolyte composed of a solution containing a compound of the soluble electrode, said device permitting a greater flow of current from the soluble electrode through the electrolyte to the inert electrode than in the opposite direction.

13. A device consisting of a soluble electrode and an inert electrode in an electrolyte composed of a solution containing a compound of the soluble electrode, said device producing no more than a negligible current and permitting a greater flow of current through the electrolyte to the inert electrode than in the opposite direction. 7

1.4:. A device consisting of a soluble electrode whose area is not limited by the character of the circuit, an insoluble electrode whose area is limited, and an electrolyte,'said device permitting a greater flow of current in one direction than in the opposite direction.

15. In an asymmetrical conductor, the combination of two electrodes with an electrolyte,

IOO

y opposite direction.

one of said electrodes being soluble and whose electromotive force is constant in direction and approximately constant in value, and the other electrode having an electromotive force Variable in direction and value. I

16. The combination of a gaseous electrode and an inert electrode with a solution containing a compound of the gaseous electrode for the purpose of permitting the flow of currentnlore freelyin one direction than in the 17. The combination. of a hydrogen electrode and an inert electrode with'a solution containing a compound of the hydrogen electrode for the purpose of permitting the flow of current more freely in one direction than in the opposite direction.

18. The combination of a gaseous electrode,

a metallic electrode, and an electrolyte for the electrode to the non-gaseous electrode by elec- 1 trolytic action to return to the gaseous electrode.

This specification signed and witnessed this 30 20th day of April, 1899.

LEO WALTER HI LDBURGH.

Witnesses: I

J. O. EDMoNDs,v WM. PELZER. 

